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Object that we can observe where all 3 types of redshifts

  1. May 24, 2008 #1

    Is there any kind of object that we can observe where all 3 types of redshifts can be clearly identified - Doppler, gravitational and cosmological?

    Thank you.

  2. jcsd
  3. May 25, 2008 #2


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    All of them. Redshift components are not easily separated. Cosmological redshift is usually the dominant component. Even super massive black holes have insignificant gravitational redshifts because most luminosity occurs too distant from the event horizon to be measurably affected. Doppler redshift is also a weak player. Proper motions - with the exception of supernova ejecta - are rarely more than a tiny fraction of the speed of light.
  4. May 25, 2008 #3


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    There is only one redshift. We can determine different physical processes that may have lead to an object having a given redshift, but observationally redshift is redshift so you can't measure anything that will tell you what caused the redshift to occur for an individual object.
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